Most public safety service delivery systems have been established to mitigate relatively short incidents. These systems rely on a quick response with resources of an adequate quantity and quality to “overpower” an event. In the event of an incident that exceeds the capacity of those resources, however, incident commanders may have difficulty adjusting.

An important tool that can assist in such circumstances, especially with establishing strategic goals and use of available resources, is the concept of “operational periods.” The National Wildfire Coordinating Group defines this term as “… the period of time scheduled for execution of a given set of operation actions as specified in the incident action plan. Operational periods can be of various lengths, although usually not over 24 hours.” Though there is limited guidance on the use of operational periods available outside of the wildfire environment, the concept is an important one, both for planning and safety.

Operational periods should be considered as segments of four, six or 12 hours, depending on the type of activity. In general, an operation period during escalating structural fire incidents shouldn't exceed four hours. This limit is predicated on the fact that fires in structures large enough to burn for more than four hours generally occur in urban settings. Urban settings also pose greater risk to life safety due to higher population densities. It's not surprising, therefore, that urban firefighters would consider interior firefighting as a tactical option more frequently.

It's commonly accepted that interior structural firefighting is one of the most hazardous activities in which a fire service responder can engage. Interior firefighting is not only labor intensive, but also physically and mentally taxing for the entire response. The four-hour time limit for a structural fire operational period allows resources to be focused and used in an intense manner, knowing that additional resources will be brought to bear in the next operational period. The four-hour operational period also is loosely based on the fact that the some states have laws or administrative rules requiring employers to provide employees with a short paid rest breaks every four hours. Though these regulations may not particularly apply to government, they are a reasonable standard to use for comparison purposes.

Incorporating a four-hour operational period in structural firefighting should be predicated on planning for the replacement of on-scene resources at the end of the four-hour period. The four-hour replacement cycle facilitates meeting two major objectives: It limits the exposure of members to injury as they fatigue, and it provides an opportunity for other members to gain valuable emergency scene experience (the latter a more difficult aspect of firefighting as the number of fires around the country diminishes).

This four-hour replacement cycle, however, makes the mobilization of additional resources a very important goal for the planning and logistics sections that are responsible for the second operational period. Though many fire departments won't have the resources to rotate personnel immediately, the recall of additional shifts of personnel or the use of mutual aid, regional and statewide mobilization will apply in these types of incidents.

For special operations, including non-structural fires, hazmat and technical-rescue incidents, and preplanned non-emergency events, the operational periods should be no longer than six hours. Often these types of incidents and events will start with a flurry of activity, then shift to a slower pace. This change in activity level can be deceptive, however, and the incident commander must guard against the transition creating a perception that the human resources on scene are doing better than they actually are. After six hours, most responders and participants will be in need of an extended period to rehydrate, replenish nutrients and have any medical conditions checked. The need for such a break isn't limited to those whose work is mainly physical; command and general staff will accumulate mental stress, as well.

Failure to address these human needs has a direct impact on the safety of the responders; it also lowers the probability of successfully completing the strategic goals of the incident action plan. Command and general staff may not need to rotate at the four-hour mark and should rarely rotate at the same time as operational resources to ensure command and control integrity. They should, however, rotate at some point, and a six-hour operational period could be a good opportunity.

Rarely should an operational period during an ongoing incident exceed 12 hours. A 12-hour operation period most likely would have applicability in disaster-related operations. Though it’s very difficult to get responders to “stand down” during an ongoing or large-scale disaster, it is incumbent on the incident commander to demand that this occur for the health and safety of the responders.

Additionally, most incident command field operations guides use 12-hour standardized planning cycles. One of the first major incidents in the county to emphasize this point was the Oklahoma City bombing, where FEMA‘s Urban Search and Rescue task forces first were used to a significant degree. The system originally envisioned a task force being able to operate for 24 hours. It became apparent almost immediately that 12-hour operational periods were much more effective and safer for the responders.

Command and general staff positions must be rotated at no later than the 13- or 14-hour mark. This allows the first operational period an overlap to brief the oncoming staff. Failure to rotate at this point could cause the quality of command decisions to degrade with the physical condition and level of mental alertness of the people in the positions.

The length of initial operational periods should be established by organizational policy and codified in the Incident Action Plan. For more routine incidents, operational periods should be preplanned based on the available resources and the type on incident. In fact, much of what the fire service has considered “preplanning” is actually planning for the first operational period. The length of the second and following operational periods should be proposed by the planning section, confirmed by the logistics section and given final approval by the incident commander. The effective use of operational periods in the planning and execution of strategic goals at an incident or event could be the deciding factor in the success or failure of the goals themselves.